class_docstr: test mixin with layout properties
docstr: test whether respective layout traits are updated when traits change
docstr_tok: ["test","whether","respective","layout","traits","are","updated","when","traits","change"]
code: def test_layout_updated_on_trait_change(self):
      "test whether respective layout traits are updated when traits change"
  
      template = self.DummyTemplate(width="100%")
      assert template.width == "100%"
      assert template.layout.width == "100%"
  
      template.width = "auto"
      assert template.width == "auto"
      assert template.layout.width == "auto"
  
imports: from unittest import TestCase
  import pytest
  import traitlets
  import ipywidgets
  from ipywidgets.widgets.widget_templates import LayoutProperties
label_desc: Use image node_id 1 for calling the TestLayoutProperties obj's underlying member method code with example usage: obj.test_layout_updated_on_trait_change() without return types